Proceedings Paper

The ABLE ACE experiment involved measurements of effects of stratospheric turbulence on the propagation of laser beams over nearly horizontal paths between two aircraft flying in the vicinity of the tropopause. The simulations described in this talk were performed in support of the ABLE ACE data reduction effort, and as a means of anchoring the validity of the propagation codes and the atmospheric turbulence models used in these codes. At the outset of this work we were unsure whether the standard turbulence models applied at the altitudes of interest. Turbulence parameters at issue in this regard are the: (1) the spectrum, (2) the inner and outer scale lengths, and (3) the strength as a function of position along the path. Most of the simulations assumed a Kolmogorov spectrum with finite inner and outer scale lengths; and we believe that the ABLE ACE data are consistent with these assumptions. Anemometer and scintillometer measurements of turbulence strength in ABLE ACE indicate that stratospheric turbulence is highly intermittent. Techniques for accounting for this intermittency in the simulations will be discussed. Comparison of simulation results and predictions of theory for weak turbulence indicates that the codes accurately model such effects.